Garden Tip #139

Eradicating blackberry vines may seem hopeless, especially if you don’t want
to use chemicals, but don’t give up just yet. The Northwest Center for
Alternatives to Pesticides advises gardeners to cut off the top growth, dig
out the main root-ball, and then follow-up by mowing all new growth.
Planting desirable plants to shade out the sun loving blackberries is also
critical. Read the NCAP’s blackberry management plan (pdf).

Garden Tip #14

A common question we get at the Elisabeth C. Miller Library is How do I kill weeds without hand digging but without using toxic chemicals? Further discussion with the gardener reveals he wants to buy a product that he can spray on the weeds, once. Organic gardeners have it easier now compared to a decade ago, with a number of less-toxic weed killers on the market, but the fact is not one of these products is a magic bullet.

Corn Gluten Meal (Concern’s Weed Prevention Plus and Whitney Farm’s Weed Whompin Mulch) is a natural product that prevents seeds from rooting once sprouted. The downside is that it doesn’t work during rainy weather. Another consideration is that recent studies show it acts as fertilizer because it is rich in nitrogen, so in garden beds it may actually increase weeds. Its best use would be for weeds in lawns, according to an article in Organic Gardening, Aug/Oct 2008.
Potassium salts of fatty acids (Safer Superfast Weed & Grass Killer) kills the tops of all plants, but not the roots. It works best on annual weeds like chick-weed and bitter cress, but would have to be repeated a few times to kill perennial weeds with root reserves, such as dandelion.
Pelargonic acid herbicide (Scythe) is another type of fatty acid, similar to soap, that kills weeds by drying out the leaves. As mentioned above this product works best on annual or biennial weeds and must be reapplied a few times to kill perennials.
Vinegar from the kitchen doesn’t kill weeds, only disfigures them. Commercial products (Burnout, Bradfield’s Horticultural 20% Vinegar) work if used in hot weather, but are quite caustic and great caution must be used not to inhale the fumes or spray the skin. Natural, yes, but toxic.

What does it take to get rid of weeds? A multi-pronged approach: physically remove weeds when they are young, reapply mulch every year, shade weeds out with desirable plants, and don’t let weeds go to seed.

The Northwest Center for Alternatives to Pesticides publishes excellent articles on non-toxic pest control. Two good articles on weed management are available free online:
Managing Weeds in Shrub and Flower Beds and Landscape Weed Control

Garden Tip #203

Ever wonder what you can do to combat global warming? The Union of Concerned Scientists has produced a guide called “The Climate-Friendly Gardener: A Guide to Combating Global Warming from the Ground Up.” The gardening choices we make can maximize carbon storage and minimize pollution. This publication discusses fertilizers, cover crops, food gardens, composting, lawn maintenance, and more. You can also sign a pledge to be a climate-friendly gardener!

Garden Tip #29

Powdery mildew season has begun (May), so act now to prevent or slow the development of this disfiguring (though not usually lethal) disease. Research published in Crop Protection demonstrated good results for preventing and managing mildew by spraying once a week with a 20%-40% solution of non-fat milk diluted in water. The down side to this organic remedy is the white residue left behind by the milk, which resembles the mildew we’re trying to cure in the first place! Other less-toxic sprays that are new to the market are:

Eco E-Rase (also sold as Detur), a jojoba oil spray that smothers mildew spores;
Citrall Organic Lawn and Garden Fungicide derived from Backhousia citriodora (Lemon Myrtle), native to Australia;
Rose Defense made with Neem oil, which is not so new, but is still unfamiliar to many gardeners.

Go online to Colorado State University for a fact sheet on powdery mildew.

Garden Tip #31

Many plants outgrow aphid infestations with no harm done. But sometimes aphids do cause permanent damage to tender shoot of young plants. If action must be taken, soft-bodied aphids can be killed by common non-toxic ingredients found at home. Here is a recipe for a spray from The Frugal Gardener by Catriona Erler (Rodale, $27.95):

1 garlic bulb
1 small onion
1 teaspoon cayenne pepper powder
1 quart water
1 tablespoon liquid dish soap

liquefy garlic and onion in a blender, then add cayenne and water. Steep for an hour. Strain the liquid through cheesecloth, then add soap. Spray directly on aphids, or on plants vulnerable to aphids, like roses. Keep away from eyes and skin. This spray may be kept refrigerated for one week.

Garden Tip #186

The Rodale family of Emmaus, Pennsylvania has a 60 year history of publishing books and magazines that promote organic gardening and their encyclopedias have come to be regarded as the standards on the subject. A good example is the Rodale’s Illustrated Encyclopedia of Organic Gardening (DK Publishing, 2002 $40.00). A must-have for serious organic gardeners certainly, but the user-friendly qualities that are a trademark of DK will make it one of the first books in a beginning gardener’s library as well.